Abstract: At the step of measurement for calibration of parallel robot, the system error will be created for the inconsistent reference frame between the spatial coordinate measuring device and the parallel robot. To eliminate the system error, the reference frame of the parallel robot is transformed to the one of the spatial coordinate measuring device at the step of modeling for calibration of parallel robot and a consistent reference frame is obtained. After simulating the process of calibration with the unimproved model and the improved model respectively to a 5-DOF parallel robot, the results indicate that the improved model can eliminate the system error completely while the unimproved model can not. So the improved model is better at improving the accuracy of calibration. The method of modeling for calibration of parallel robot has a highly use value.

Key words: Calibration, Modeling, Parallel robot, System error